Skip to content

Course home

2.3 Probability

2.3 Probability

EasyMediumHard
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163
Question 19

Two boxes, X X\,X and YYY, contain red, blue, and green pens. Box X X\,X contains 2 red pens, 5 blue pens, and 3 green pens. Box Y Y\,Y contains 6 red pens, 2 blue pens, and 2 green pens. Casey picks one pen at random from Box X X\,X and places it into Box YYY. Casey then picks one pen at random from Box YYY.

a.

Draw a tree diagram to represent this information.

[2]
b.

Find the probability that Casey picks two pens of the same colour.

[2]
c.

Given that both pens are the same colour, find the probability they are both blue.

[2]
Markscheme

2.3 Probability Questions

  1. A Level
  2. /Maths
  3. /2.3 Probability

200 exam-style questions on OCR A Level Maths 2.3 Probability, covering 2.3.1 Mutually exclusive and independent events, 2.3.2 Diagrams to assist probability calculations, 2.3.3 Conditional probability (A-level only), 2.3.4 Conditional probability from first principles (A-level only), and 2.3.5 Modelling with probability. Each one has a worked solution and a mark scheme showing where the marks go.

Question bank